VB Performance issues

Hello,

My colleague and I have an application we developed in VBA, having sorted it
out and tracked down the bugs we then ported it over to VB6 using the VBADEV
manual for guidance. the application compiles and runs OK except for one
thing, it is dead slow. If for example in VBA it would run in 30seconds it
now takes 5 minutes. The application basically sets two
document/application variables AcadApp and AcadDoc as per the manual and
uses them like this.

Set TextObj = AcadDoc.ModelSpace.AddText(TextVal, ptb, tsize)

All this is as per the manual. Can anyone suggest what could be wrong and
hopefully suggest a fix for us.

Thanking you un advance for any help you can offer

Regards


Martin Duke

 

Are you using late bound or early bound objects?

ie.

' Late bound: The application must look up the
' property/function each time it is called at run time
' (slower)
Dim TextObj as Object

' Early bound: the application knows at compile time
' what the object is. (= faster)
Dim TextObj as AcadText


Even using early bound objects, calls to autocad will typically be
slower as it is out of process and vb must communicate between process
boundaries. However, I wouldn't expect it to be that slow unless
there are lots of repeated calls to autocad objects.

Tips:

1. Use early bound instead of late.

2. Use the With statement when making many calls to the same object,
especially when you are not referencing the object directly. ie.

With AcadDoc.ModelSpace
Loop
Set TextObj = .AddText(TextVal,ptb,tsize)
TextObj.Alignment = acAlignmentBottomCenter
etc...
End Loop
End With

3. Avoid unnecessary calls/references to autocad objects. ie.
Instead of repeatedly referencing TextObj.TextString, save it to a
local variable, do the processing, then copy it back..

ie.
Dim sTemp As String

sTemp = TextObj.TextString
'Processing..(Change references from TextObj.TextString to sTemp)
TextObj.TextString = sTemp


4. Determine which parts of your code are causing the most problems
and focus on optimizing them. If you find a particular routine is
unexpectedly slow and you can't solve it, the post the specific
problem area.

-Tim

 

Tim,

Thank you for those suggestions. We are definitely using early binding, so
I think we can eliminate that. The use of the With statement is something
we will implement, but as for the rest we pretty much work as you suggest.
I was wondering if there was a way to halt autocad doing anything while the
App is doing it's work. I think that because the app is running
independantly it takes too long to pass an instruction to AutoCAD.


Anyway thank you for all your help

Kind Regards



Martin Duke